Abstract Section The proposed project, the Men's Domestic Abuse Check-Up (MDACU), will evaluate a telephone-delivered Motivational Enhancement Therapy (MET) intervention for untreated and non-adjudicated substance-abusing men who are intimate partner violence (IPV) perpetrators. The objective is to contribute to the cessation of substance abuse (SA) and IPV which in turn protects victims, their children, and society from the adverse psychological, economic, and health-related consequences of violence (e.g., HIV infection) in the home. The findings from our first trial offer considerable promise for the check-up with substance-abusing perpetrators. A second Stage lb trial is proposed for the following reasons: (1) the intervention has potential for prevention of further IPV and SA;(2) the experience of conducting the previous trial supports the likelihood of greater efficacy if several components of the experimental intervention are substantially revised;(3) the feasibility of expanding the window of time in which post-treatment behavioral and treatment engagement outcomes are assessed is important to test;(4) assessing the feasibility of obtaining corroborative data partners, treatment providers, and arrest records is important;(5) preliminarily evaluating HIV risk behaviors in the context of IPV and SA is significant;and (6) the Theory of Planned Behavior (TPB) may provide insight into how this intervention works with IPV perpetrators. These enhancements are significant enough to warrant a second Stage lb study to determine if a Stage II project is warranted (Rounsaville, Carroll, &Onken, 2001 ). This study is predicated on the following premises: (a) a substantial number of substance abusers and perpetrators of IPV engage in both behaviors concurrently, however the majority are unreported to authorities and remain untreated;(b) a percentage of them are likely to have episodic internal conflict concerning their SA and IPV;(c) a marketing campaign can motivate these individuals to "take stock" of their behaviors and !heir behavior change options;(d) an anonymous telephone service will reduce barriers to the voluntary initiation of contact by unreported perpetrators;and (f) the study's MET intervention can effectively motivate individuals to take steps (e.g. entering treatment in the community) toward ending IPV and SA. The specific aims are to: (1) revise the current treatment manual to incorporate an enhanced MET intervention (including discussion of treatment resources);(2) pilot-test protocols for the collection of data from spouses/partners, treatment providers, and the criminal justice system in order to corroborate participant selfreport;(3) using elicitation interviews, develop a questionnaire on salient beliefs (norms, self-efficacy, outcomes) about the behavioral outcome being modeled by the TPB (i.e., intake and assessment attendance at a community IPV agency);(4) conduct a pilot study in which effect sizes for key outcomes are determined and the theoretical foundation (mediators and moderators) for the intervention is explored;and (5) investigate the association between H IV risk behaviors in the context of SA and I PV.